Fig. 4: Delta-rhythmic neurons, but not non-delta neurons, exhibit locomotion-dependent spiking.

a An example locomotion speed recording (black line) while an animal was voluntarily running on the treadmill. The dashed blue line indicates the threshold (5 cm/s) used to classify periods of rest (pink) and movement (green). Blue dots mark the onset and offset of movement periods. The schematic resting mouse was adapted from https://doi.org/10.5281/zenodo.3925949 and running mouse from https://doi.org/10.5281/zenodo.3925901. b Firing rates in delta-rhythmic neurons during rest versus movement (paired t-test, p = 0.0026, n = 31, df = 30). c Same as b, but for non-delta neurons (paired t-test, p = 0.556, n = 21, df = 20). d Left: Interburst firing rates of delta-rhythmic neurons during rest versus movement (paired t-test, p = 0.005, n = 31, df = 30). Right: Intraburst firing rates of delta-rhythmic neurons during rest versus movement (paired t-test, p = 1.7 × 10^–5, n = 31, df = 30). e Spike raster plot aligned to movement onset for an example ChI. Black points are spike times, and the red line indicates the average firing rate across all movement onsets. f, g Population firing rate aligned to movement onset for (f) delta-rhythmic neurons (n = 31) and (g) non-delta neurons (n = 21). Turquoise lines indicate running speed. h Quantification of movement onset-related firing rate changes calculated as post-onset (0 to 120 ms) minus pre-onset (−120 to 0 ms). Only delta-rhythmic (D) ChIs increased their firing rates at onset (all one-sample t-test, ChI, D: p = 0.019, n = 21, df = 20, one neuron excluded due to lack of movement data; SYN, D: p = 0.099, n = 9, df = 8; SYN, non-delta (ND): p = 0.53, n = 16, df = 15). Delta-rhythmic SYNs had significantly stronger firing enhancement than non-delta SYNs (independent t-test SYN D vs SYN ND: p = 0.041, n = 25, df = 23). The shaded regions around line plots represent the standard error of the mean. Quantifications are visualized as violin plots with the outer shape representing the data kernel density and a box-and-whisker plot (box: interquartile range, whiskers: 1.5x interquartile range, white line: mean). All statistical tests are two-sided. Source data are provided as a Source Data file.